This paper presents a novel approach for tuning substrate integrated waveguide resonators, realized by placing an additional metallized via-hole on the waveguide cavity. The approach presented here can be applied as a trimming technique, as well as to develop filter designs with tunable center frequencies and tunable bandwidths. Three different filters are designed and implemented, demonstrating excellent trimming, 10% tuning of the center frequency, and 100% tuning of the bandwidth, respectively.

An equivalent circuit model to predict lateral modes occurring in real BAW resonators is proposed. The circuit model has been validated with FEM simulations of FBAR resonators and also with measurements of SMR resonators. The model allows to predict the electrical response of square-shaped and rectangular-shaped resonators without limitation on dimensions.

This letter describes a novel absorptive limiter for frequency-selective circuits. The proposed circuit allows the design of absorptive limiters based on a bi-state phase shifter, which is appropriate for integration into channelizing devices, such as hybrid-coupled input multiplexers. A preliminary prototype with shunt PIN diodes has been fabricated and measured to demonstrate the viability of the concept.

This paper demonstrates that it is possible to find an ideal filter response (Chebyshev, Butterworth,..) considering the antenna as the last resonator of a filter under certain circumstances related with the antenna performance and the bandwidth of the filtenna device. If these circumstances are not accomplished, we can achieve excellent performance as well, by means of an iterative process the goal of which is defined by either a filter mask or a classical filter function itself. The methodology is based on the conventional coupling matrix technique for filter design and has been validated by fabricating a microstrip prototype using hairpin resonators and a rectangular patch antenna.

This paper evaluates the nonlinear effects occurring in a bulk acoustic wave (BAW) filter which includes barium strontium titanate (BST) capacitors to cancel the electrostatic capacitance of the BAW resonators. To do that we consider the nonlinear effects on the BAW resonators by use of a nonlinear Mason model. This model accounts for the distributed nonlinearities inherent in the materials forming the resonator. The whole filter is then implemented by properly connecting the resonators in a balanced configuration. Additional BST capacitors are included in the filter topology. The nonlinear behavior of the BST capacitors is also accounted in the overall nonlinear assessment. The whole circuit is then used to evaluate its nonlinear behavior. It is found that the nonlinear contribution arising from the ferroelectric nature of the BST capacitors makes it impractical to fulfill the linearity requirements of commercial filters.

We present the electro-thermo-mechanical constitutive relations, expanded up to the third order, for a BAW resonator. The relations obtained are implemented into a circuit model, which is validated with extensive linear and nonlinear measurements. The mathematical analysis, along with the modeling, allows us to identify the dominant terms, which are the material temperature derivatives and two intrinsic nonlinear terms, and explain, for the first time, all observable effects in a BAW resonator by use of a unified physical description. Moreover, the terms that are responsible for the second-harmonic generation and the frequency shift with dc voltage are shown to be the same.

In this work we go beyond the usual temperature range for commercial applications and explore the functioning of Bulk Acoustic Wave (BAW) resonators down to cryogenic temperatures, to get the whole picture at understanding the physical tendency of the main parameters with temperature. This can ensure the proper functioning for specific applications where the device is exposed to extreme temperature variations.

We present a methodology to characterize BAW resonators both linearly and nonlinearly. The procedure uses physical modeling along with measurements that exploit different manifestations of the nonlinear phenomena to identify the dominant linear and nonlinear material properties. Such methodology allows obtaining consistent nonlinear material parameters by use of two independents measurements.

We present a methodology to characterize BAW
resonators both linearly and nonlinearly. The procedure uses physical modeling along with measurements that exploit different
manifestations of the nonlinear phenomena to identify the dominant linear and nonlinear material properties. Such methodology allows obtaining consistent nonlinear material
parameters by use of two independents measurements.

This letter presents a novel approach for providing
substrate-integrated waveguide tunable resonators by means of
placing an additional metalized via-hole on the waveguide cavity.
The via-hole contains an open-loop slot on the top metallic wall.
The dimensions, position and orientation of the open-loop slot
defines the tuning range. Fabrication of some designs reveals good
agreement between simulation and measurements. Additionally,
a preliminary prototype which sets the open-loop slot orientation
manually is also presented, achieving a continuous tuning range
of 8%

The design, modeling, fabrication, and characterization
of a vibrationally trapped thickness-shear MEMS resonator
is presented. This device is intended to avoid various limitations
of flexural MEMS resonators, including nonlinearity, clamping
losses, thermoelastic damping, and high damping in liquid. It
includes a silicon bridge and a reference line on an SOI wafer,
a coupled Au/Cr coplanar waveguide, Lorentz-force coupling,
variations in waveguide thickness for vibrational trapping, and
circuitry for nulling the components of the signal that are
unrelated to the acoustic resonance. Finite-element vibrational
modeling shows the lowest thickness-shear mode with a bridge
thickness of 4.9 µm to be dominated by shear displacements,
with the magnitude of out-of-plane displacements decreasing with
increasing bridge width. Two-dimensional modeling of vibrational
trapping, with central regions of the waveguides having
43 nm greater thickness, indicates that amplitudes are reduced
by several orders of magnitude at the ends of the bridges for
the fundamental ~ 400 MHz thickness-shear resonance. Sweptfrequency
network-analyzer measurements of fabricated devices
reveal no evidence for an acoustic resonance, despite a calculated
prediction of levels of acoustic power absorption that are well
above the measured noise level. A possible explanation for this
result is stiction of the bridges to the substrate.

The telecommunications industry follows a tendency towards smaller devices, higher power and higher frequency, which imply an increase on the complexity of the electronics involved. Moreover, there is a need for extended capabilities like frequency tunable devices, ultra-low losses or high power handling, which make use of advanced materials for these purposes. In addition, increasingly demanding communication standards and regulations push the limits of the acceptable performance degrading indicators. This is the case of nonlinearities, whose effects, like increased Adjacent Channel Power Ratio (ACPR), harmonics, or intermodulation distortion among others, are being included in the performance requirements, as maximum tolerable levels.
In this context, proper modeling of the devices at the design stage is of crucial importance in predicting not only the device performance but also the global system indicators and to make sure that the requirements are fulfilled. In accordance with that, this work proposes the necessary steps for circuit models implementation of different passive microwave devices, from the linear and nonlinear measurements to the simulations to validate them. Bulk acoustic wave resonators and transmission lines made of high temperature superconductors, ferroelectrics or regular metals and dielectrics are the subject of this work. Both phenomenological and physical approaches are considered and circuit models are proposed and compared with measurements. The nonlinear observables, being harmonics, intermodulation distortion, and saturation or detuning, are properly related to the material properties that originate them. The obtained models can be used in circuit simulators to predict the performance of these microwave devices under complex modulated signals, or even be used to predict their performance when integrated into more complex systems. A key step to achieve this goal is an accurate characterization of materials and devices, which is faced by making use of advanced measurement techniques. Therefore, considerations on special measurement setups are being made along this thesis.

This work proposes a superconducting multiplexer filter bank configuration to be used as a frequency-selective power limiter. The proposed configuration limits narrowband high-power signals within a single frequency band without degrading the signal performance in the rest of the frequency bands. To accomplish this, we need to calculate the limiting power of superconducting filters implemented by means of half-wavelength transmission line resonators. The limiting power is obtained as a function of the resonator geometry, filter bandwidth, and filter order. Practical issues occurring in superconducting filters operating at high power, such as the reduction of the quality factors and de-tuning, are also analyzed and shown to not adversely affect the overall multiplexer power limiter performance.

Aspect-Oriented Software Development (AOSD) supports systematic identification, modularisation, representation and composition of crosscutting concerns such as security, mobility, distribution and resource management. Its potential benefits include improved ability to reason about the problem domain and corresponding solution; reduction in application code size, development costs and maintenance time; improved code reuse; architectural and design level reuse by separating non-functional concerns from key business domain logic; improved ability to engineer product lines; application adaptation in response to context information and better modelling methods across the lifecycle.AOSD-Europe will harmonise and integrate the research, training and dissemination activities of its members in order to address fragmentation of AOSD activities in Europe and strengthen innovation in areas such as aspect-oriented analysis and design, formal methods, languages, empirical studies and applications of AOSD techniques in ambient computing. Through this harmonisation, integration and development of essential competencies, the AOSD-Europe network of excellence aims to establish a premier virtual European research centre on AOSD. The virtual research centre will synthesise the collective viewpoints, expertise, research agendas and commercial foci of its member organisations into a vision and pragmatic realisation of the application of AOSD technologies to improve fundamental quality attributes of software systems, especially those critical to the information society. It will also act as an interface and a centralised source of information for other national and international research groups, industrial organisations and governmental bodies to access the members? work and enter collaborative initiatives. The existence of such a premier research base will strengthen existing European excellence in the area, hence establishing Europe as a world leader.

This paper studies the practical challenges that arise due to the coexistence of two wireless technologies, both operating in the license-exempt 5 GHz band. In particular, WiFi and WiMAX equipment have been used in the experiments. The mutual interference caused by the two technologies operating
in different but narrowly separated frequency channels has a negative impact on
the performance of both systems. Further challenges are introduced when the two systems are in close physical proximity of each other or, in a more extreme scenario, share the same antenna as could be required in railway applications.
This paper investigates these issues through a series of experimental tests based on a multi-radio platform testbed. The conclusions drawn from this study will be used as a base for the implementation of a multi-radio platform to provide communications between train and land in both directions in the context of the
Spanish high-speed railway system.

'Current 4G vision envisages higher data rates and multi standard radio interfaces to provide all users with a continuous seamless connection. The large number of foreseen devices coupled with the surge in power requirements for future emerging handsets raises significant challenges in terms of: i) reducing the energy consumption; and ii) reducing the amount of electromagnetic radiations.
GREENET targets the following main objectives:
1. Recruitment of ESRs with the clear and long-term objective to conduct top-notch research and to pursue research excellence at the national, European, and international levels.
2. Develop training and career plans that are personalized as possible to meet the needs and desires of each ESR.
3. To allow the ESRs to understand and address key research challenges on energy efficient GREENET communications, that form pivotal societal and economic concerns for Europe within the mid-to-long term.
4. Offer to each ESR top-level training and research programs with the twofold objective to reinforce and corroborate their own background, as well as to complement this with active participation in a multi-disciplinary network of research scientists.
5. Complement the typical competences of “applied research” with aspects related to project management, intellectual property rights, writing of patents, presentation and communication skills, writing of technical papers, exploitation of technical results and creation of start-up companies, etc.
6. Guide and help the ESRs to build the bridge from academia to a remarkable and untactful professional career in either the private or public sectors.'

In this work, a model that uses several nonlinear parameters to predict harmonics and 3IMD distortion is presented. Its novelty lies in its ability to predict the nonlinear effects produced by self-heating in addition to those due to intrinsic nonlinearities in the material properties.
The model can be considered an extension of the nonlinear KLM model (originally proposed
by Krimholtz, Leedom and Matthaei) (Krimholtz et al., 1970) to include the thermal effects due to self-heating caused by viscous losses and electrode losses. For this purpose a thermal domain circuit model is implemented and coupled to the electro-acoustic model, which allows us to calculate the dynamic temperature variations that change the material properties. In comparison to (Rocas et al., 2009), this work describes the impact that electrode losses produce on the 3IMD, presents closed-form expressions derived from the circuit model and validates the model with extensive measurements that confirm the
necessity to include dynamic self-heating to accurately predict the generation of spurious
signals in BAW devices.

Lossy synthesis techniques are used to synthesize high performance filters using resonators with a finite Q. With these techniques a transmission response of a lossless filter with lowest possible roll-off is obtained, except for an overall constant additional insertion loss. The out-of band performance is not affected. These types of filters are useful in receiver architectures where the filter can be placed following an amplifying stage and some increase in insertion loss can be tolerated without affecting the noise figure. Due to the lower resonator Q that can be employed, low cost and compact filters (such as microstrip filters) can be realized.
Hence this work presents the synthesis and design of two planar lossy filters. Both filters have been designed using microstrip technology, with center frequencies of 1 GHz and 1.6 GHz, and bandwidth of 36 MHz and 80 MHz, respectively. Both filters exhibit a flat in-band response with an insertion loss of 10 dB and 7.5 dB, respectively. The topologies obtained from the synthesis result in a 4th and a 6th order filters at 1 GHz and 1.6 GHz, respectively. Both topologies present a uniform Q distribution throughout the networks, this is all the resonators of the filter are equal to 200 and 290, respectively. In contrast with conventional filter networks, where all the couplings are reactive, lossy filters require some of the couplings to be resistive. The main difference between the two filters presented is the type of frequency response. While the filter at 1 GHz synthesizes a response with a stopband 10 dB return loss, the filter at 1.6 GHz synthesizes a purely reflective response in the stopband.
The presentation will also show details of the software package that has been written to synthesize filters following various forms of pre-distortion, classical (no-loss considered in the synthesis) and lossy filter synthesis. This software obtains the coupling matrix of several network topologies for a given response and allows performing rotations on them to find the desired topology. Additionally, the software allows to evaluate the effect of loss in the networks resulting from the synthesis, even in those cases where the synthesis results in an ideal lossless network (i.e., classical and pre-distortion synthesis).

This work expands the model proposed by Krimtholz,
Leedom, and Matthaei (KLM) model to account for the nonlinear
effects occurring in acoustic devices due to the nonlinear stiffened
elasticity.We show that a nonlinear distributed capacitance in the
acoustic transmission line of the KLM model can account for the
distributed nature of the nonlinear effects. Specifically, we use the
nonlinear telegrapher’s equation to find closed-form equations for
intermodulation distortion and harmonic generation. We confirm
the validity of these equations by comparing their results with those
provided by aKLMequivalent circuit in which the nonlinear transmission
line is implemented by cascading many L-C cells having
a voltage-dependent capacitance. To further confirm the model, we
show measured nonlinear effects in a thin film bulk acoustic resonator
in close agreement with the equivalent circuit simulations.